A wide variety of cups specifically designed for use by infants and children are commercially available. In such cups, it is advantageous to have a feature that prevents spilling or leaking if the cup is accidentally knocked over or used in a moving vehicle where the liquid could be spilled by normal movement.
Currently there are cups commercially available that incorporate a valve feature in the lid of the cup to prevent spilling or leaking. The valve feature includes a drinking valve that permits the liquid to exit from the drinking cup and a vent valve to allow ambient air into the drinking cup. When the consumer using the cup drinks from the drinking spout, the drinking valve opens and allows liquid to come out. At the same instant, the vent valve responds to the suction on the drinking valve and opens to allow ambient air into the cup. Examples of such valves are shown in FIGS. 1 and 3.
The valve assembly of the currently available leak proof cups is designed to be “normally closed.” This means that the drinking valve is closed unless a force is applied. Thus, if the drinking cup is knocked over, even if there is a small amount of hydrostatic pressure due to the liquid in the cup, no liquid will come out the drinking spout or vent. Without a small amount of vacuum or suction applied to the drinking valve, it is not possible for liquid to come out of the drinking cup.
Despite the benefits, there are a number of issues with the currently available leak proof cup valve designs. One problem with the current valve designs is that cleaning of the valve is difficult as the valve needs to be opened to flush out any remaining liquid, such as milk or fruit juices. Failure to properly clean and sterilize the valve assembly can result in spoilage and possible illness.
Another problem with the current valve designs is that the valve assembly can be dislodged if the cup is dropped. In this case, not only can liquid spill out, but, with the valve removed, an unexpected large volume of liquid can exit the drinking spout when the cup is used, which can lead to choking.
The lid and valve design described herein addresses the need to provide an easy-to-clean valve assembly for leak proof cups that attaches to the lid of the cup in such a way that it is not dislodged when dropped.